Cell cycle-dependent regulation of SFK, JAK1 and STAT3 signalling by the protein tyrosine phosphatase TCPTP.
Janus-activated kinases (JAKs) and Src family kinases (SFKs) and their common substrate signal transducer and activator of transcription (STAT)-3 are frequently hyperactivated in human cancer contributing to the proliferative drive by promoting G(1)/S and G(2)/M progression. Previous studies have established that the protein tyrosine phosphatase TCPTP can dephosphorylate and inactivate the SFK and JAK protein tyrosine kinases (PTKs) to attenuate cytokine signalling in vivo. In this study we determined whether TCPTP regulates SFK and JAK signalling during the cell cycle. We used primary mouse embryonic fibroblasts (MEFs) isolated from TCPTP(-/-) versus +/+ mice, immortalised TCPTP(-/-) MEFs versus those reconstituted with physiological levels of TCPTP and HeLa cells in which TCPTP protein levels had been suppressed by RNA interference, to establish TCPTP as a negative regulator of SFK, JAK1 and STAT3 signalling during the cell cycle. We found that the progression of TCPTP-deficient MEFs after the G(1) restriction point into S-phase was enhanced. We used RNA interference and pharmacological inhibitors to demonstrate that elevated SFK and downstream phosphatidylinositol 3-kinase signalling but not JAK1 or STAT3 signalling were required for the enhanced G(1)/S transition. These results identify TCPTP as a negative regulator of the cell cycle.
Shields
Ben J
BJ
Department of Biochemistry and Molecular Biology, Monash University, Victoria, Australia.
Court
Naomi W
NW
Hauser
Christine
C
Bukczynska
Patricia E
PE
Tiganis
Tony
T
D000818:Animals; D002453:Cell Cycle / Q000187:drug effects; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D016193:G1 Phase / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D053613:Janus Kinase 1 / Q000378:metabolism*; D051379:Mice; D008938:Mitosis / Q000187:drug effects; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D054578:Protein Tyrosine Phosphatase, Non-Receptor Type 2 / Q000172:deficiency / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000378:metabolism; D016196:S Phase / Q000187:drug effects; D050796:STAT3 Transcription Factor / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013449:Sulfonamides / Q000494:pharmacology; D019061:src-Family Kinases / Q000378:metabolism*
D007211:Indoles; D034741:RNA, Small Interfering; D050796:STAT3 Transcription Factor; C416927:SU 6656; D013449:Sulfonamides; D019869:Phosphatidylinositol 3-Kinases; D053613:Janus Kinase 1; D019061:src-Family Kinases; D054578:Protein Tyrosine Phosphatase, Non-Receptor Type 2